Fixing apparatus

ABSTRACT

A fixing apparatus for the releasable fixing of at least one functional component, in particular in the form of a tool holder ( 1 ), on a further functional component, in particular in the form of a tool disc ( 3 ), about at least one fixing axis ( 5 ), wherein the two functional components in each case have a bearing surface ( 7, 9 ) for bearing mutually against one another, and both one functional component and the other functional component have at least one fixing element ( 11, 13 ), is characterized in that, in order to form the fixing elements ( 13 ), one functional component has two fixing bodies ( 19 ) which are connected in a positionally unchangeable manner to the associated functional component on both sides of the fixing axis ( 5 ) and at a spacing from one another, and in that each fixing body ( 19 ) forms a fixing surface ( 25 ) which extends transversely with respect to the fixing axis ( 5 ), which fixing surfaces ( 25 ) which can both be placed from the same side against an associated positioning surface ( 17 ), which are situated as fixing elements ( 11 ) on the other functional component at a spacing from one another.

The invention relates to a fixing apparatus for releasably fixing at least one functional component, in particular in the form of a tool holder, on a further functional component, in particular in the form of a tool disk, about at least one fixing axis, wherein the two functional components each have a bearing surface for mutual contact with one another, and both one functional component and the further functional component have at least one fixing element.

Tool disks are used in industrial manufacturing in combination with so-called tool turrets. If several tool holders with associated tools (e.g:, stationary cutting chisels or driven milling tools) are placed over the circumference of the tool disk, then turning this arrangement allows for quick changing of the tools, which is required for certain machining operations. Since only minimal manufacturing tolerances are generally allowed for machining workpieces, it is essential for using such tool turrets in a meaningful way that the respective tool holder and thus the respective tool be fixed in a repeatable and exactly defined position relative to the tool disk.

EP 0 780 179 B1 teaches a fixing apparatus of the aforementioned type. This device as a fixing element incorporates a projecting molded body on the tool holder and provides a recess as a fixing element at the respective tool station of the tool disk, which recess receives the molded body of the tool holder when the bearing surface of the tool holder contacts the bearing surface of the tool disk, whereby the molded body and the recess free of play engage one another to position the tool holder on the tool disk. To obtain the required predetermined position for operating the tool holder, the fixing elements are adjustable relative to the tool holder and tool disk. With the prior art device, in this regard one proceeds by aligning the fixing element with the respective tool station of the tool disk by means of a master tool holder, fixing it in a position thus adjusted by means of screws. For the corresponding adjustment of the fixing element of the tool holder, a master tool station with a pre-adjusted fixing element is provided on the tool disk. At the tool holder attached on this master tool station, the fixing element of the tool holder is then also appropriately adjusted and likewise fixed by screws. Given the need to provide master components and performing adjustments, tool holders equipped with the prior art fixing apparatus become relatively complicated and costly in operation.

Accordingly, the object of the invention is to make available a fixing apparatus characterized by being particularly easy to handle during operation and relatively inexpensive to construct.

This object is achieved according to the invention by a fixing apparatus having the features specified in claim 1 in its entirety.

According to the characterizing part of claim 1, an important feature of the invention consists in providing two fixing bodies to form fixing elements on one of the functional components, which fixing bodies, spaced apart on both sides of the fixing axis, are in fixed-position connection to the associated functional component, whereby each fixing body forms a transverse fixing surface relative to the fixing axis, both of which from the same side may be placed against an associated positioning surface, which as fixing elements are located spaced apart on the other functional component. Due to the fixed-position connection of the fixing body forming the fixing surface with the associated functional component, no adjustments of the fixing elements are needed, thus simplifying handling. Compared with prior art fixing elements in the form of interlocking form locking elements, the invention is characterized by a simplified design, as the fixing surfaces of both fixing bodies may be placed from the same side against the associated positioning surface of the other functional component, thus obviating the need for forming interlocking, free of play, form locking elements.

In an especially advantageous manner, the respective fixing surface may be formed on an integral fixing cam with the respective fixing body, with the fixing surface projecting from the bearing surface and defining a transverse fixing plane relative to the fixing axis.

The arrangement may here be implemented in an especially advantageous manner such that the fixing elements of the other functional components, preferably the tool disk, have a recess in their bearing surface for forming the respective positioning surface for each fixing surface, which recess is bounded on one side by a wall portion forming the positioning surface. Thus, all components of the fixing apparatus are situated within the perimeter of the supporting surface, e.g., the tool disk, so that on the latter, no lateral, axially protruding parts of the fixing apparatus are found.

In especially advantageous embodiments, the fixing bodies are formed by a respective strip member mounted on opposite side faces of a rectangular base plate of the tool holder.

It may be especially advantageous here to provide for the strip members to be attached to the base plate by a means of a threaded connection, where the plate comprises form locking elements for forming a precision-fit connection without the use of an adjusting device.

The arrangement may here be implemented in a particularly advantageous manner such that each threaded connection for forming the precision-fit form locking between the screw and the associated holes in the strip member and base plate has a bushing seated snugly on the screw, whereby the outer circumference of said bushing forms a fit with the holes of the strip member and the base plate. The threaded connection thus designed ensures fixation in an unchangeable position of the strip member as a result of the form locking formed at the external circumference of the bushing between the base plate and strip member and also by precluding any screw backlash due to the precision-fit of the bushing seated on the screw.

In a particularly advantageous manner, the strip members extend over a majority of the length of the relevant side face of the base plate, with a screw being provided at each end portion of the strip members.

The invention is explained in detail below with reference to an embodiment shown in the drawing, where

FIG. 1 represents a perspective, broken, and exploded oblique view of a circumferential portion of the tool disk of a tool turret showing a tool holder in a position raised away from the receiver of the tool disk;

FIGS. 2 and 3 represent broken partial top views of a tool station of the tool disk, providing a partially visible sectional view inside the tool disk of the splined shaft of a tool holder before and in the clamped state of the shaft;

FIG. 4 represents a broken perspective oblique view of the tool disk in the area of the bearing surface of a tool station; and

FIG. 5 represents an enlarged partial longitudinal section of the area of a threaded connection between the tool holder and a fixing body according to the embodiment of the fixing apparatus to be described.

FIG. 1 shows an exploded view of an embodiment of the fixing apparatus according to the invention for releasably fixing at least one functional component, present in the form of a tool holder 1, on a further functional component, here in the form of a tool disk 3, about at least one alignment axis 5 extending in vertical alignment, as viewed in the line of sight in FIG. 1. On their adjacent facing sides, the tool holder 1 and the tool plate 3 have bearing surfaces 7 and 9, respectively, which contact one another in the fixed state of the tool holder 1.

Fixing elements 11 and 13 are present both on the bearing surface 9 of the tool disk 3 and the bearing surface 7 of the tool holder 1, which fixing elements, when brought into paired interaction with one another, ensure fixation of the tool holder 1 on the tool disk 3 in relative positioning with respect to alignment axis 5. The fixing elements 11 of the tool disk 3 have in the bearing surface 9 two recesses 15, which are situated on the two opposite side edges of the tool disk 3 at equal distances from an edge of the respective bearing surface 9 adjacent to the next following bearing surface 9. The recesses 15 have, as is best shown in FIGS. 2, 3, and 4, the shape of a groove which is bounded by parallel walls at the opening, and the said groove expands on the interior end in a curved manner. With the side wall situated on the left side in FIGS. 2 to 4, the recess 15 thereby forms a positioning surface 17 in a fixing plane extending transversally relative to the alignment axis 5.

The fixing elements 13 on the tool holder 1 have two fixing bodies 19 mounted on opposite side faces 21 (FIG. 5) of the rectangular base plate 23 of the tool holder 1 forming the bearing surface 7. As explained in more detail below, the fixing bodies 19 are mounted on the tool holder 1 in unchangeable positions, i.e., non-adjustably. The fixing bodies 19 are provided on those side faces 21 of the base plate 23 corresponding with the side edges of the tool disk 3, in which the recesses 15 open out. In accordance with this positional relationship, fixing surfaces 25 provided for interaction with the positioning surfaces 17 of the tool disk 3 are located on the fixing body 19, which fixing surfaces are located on the fixing bodies 19 each in proximity to the end of the side face 21 of the base plate 23.

The fixing surfaces 25 are formed by the straight side faces of the fixing cams 27 integrated in the fixing bodies 19 and protruding from the plane of the bearing surface 7. As can be seen in FIG. 1, the fixing bodies 19 are in the shape of strip members, with each extending on the respective side face 21 of the base plate 23 substantially along their entire length. At both stepped end portions of the bodies 19, a threaded connection 29 is provided for fixed-position attachment to the base plate 21 of the tool holder 1, with the particulars of this threaded connection being shown in more detail in FIG. 5. Moreover, the said side faces may also be spherically designed.

As shown in FIGS. 1 to 3, the tool holder 1 has a pin 31 as a holding part in the center of the bearing surface 7, which pin contains an indented surface 33 on the side facing away from the observer in FIG. 1, i.e., on the side facing right in FIGS. 2 and 3, in which a corresponding clamping member 35 with its indentation 37 (FIG. 2) may engage, when inserting the pin 31 into a receiving hole 39 of the tool disk 3 located centrally in the bearing surface 9. As shown in FIGS. 2 and 3, the clamping member 35 may be clamped by means of a clamping screw 41 with the indentation 37 in order to tighten the tool holder 1 on the tool disk 3. FIG. 3 shows this situation. The clamping member 35 is brought forward via a feed hole 43 formed in the side face of the tool disk 3 and accordingly screwed in place. The locking engagement achieving this is common in the art and the subject of e.g., DIN 69880. By tightening the clamping screw 41, a starting torque is applied via the pin 31 to the tool holder 1 in the direction of the tool disk 3, so that a high contact pressure will make the two corresponding bearing surfaces 7, 9 bear against one another by involving the pairwise interacting fixing and positioning surfaces 17, 19 for positioning the tool holder 1 relative to the tool disk 3.

As mentioned above, the fixing bodies 19 with the integrally formed fixing surface 25 thereon are in fixed-position connection with the tool holder 1. This is achieved by means of the threaded connections 29, which comprise form locking elements, shown in more detail in FIG. 5, whereby a precision-fit connection, without screw backlash, is formed. For this purpose, both the hole 45 in the fixing body 19 and the hole 47 in the base plate 23 of the tool holder 1, at their mutually facing ends, have a step 49 and 51, respectively, widening the hole diameter. A fitting bushing 55 is arranged on the screw 53 and precision-fit seated on the fixing screw 53, which penetrates the holes 45 and 47, whereby the outer circumference of the fitting bushing is snugly seated in the expansions of the holes 45, 47 formed by the steps 49, 51.

Thus, when tightening the screw 53, a form locking connection between the fixing body 19 and the base plate 23, i.e., a non-adjustable connection between the fixing surface 25 and the tool holder 1, is created. When operating the fixing apparatus for the first time, one therefore proceeds by mounting the strip members 19, initially with unmachined fixing surfaces 25, on the tool holder 1, and centering it by means of the precision-fit bushings 25. Thus, after tightening the screws 53, the fixing bodies 19 are no longer adjustable. In accordance with the requirements of the high-precision definition of the position of the positioning surfaces 17 on the tool disk 3, the two fixing surfaces 25 of the fixing bodies 19 are then finished. After finishing with high precision, fixation in a predetermined position is achieved without the need of any adjustments.

A preferred embodiment of the solution according to the invention provides that the respective fixing body 19 be slotted comparable to the subsequently published DE 10 2009 033 805.5, and in accordance with the illustrations of FIGS. 4, 4 a, and 4 b of the subsequently published document. The pertinent longitudinal slot 57 divides the strip member 19 into two mutually connected segments at the bottom with the reference numerals 59 and 61. Thus, the strip-shaped fixing body 19 is implemented in a slotted manner, while forming two interconnected strip members 59, 61, whereby one strip member 59 with the fixing surface 25 connected with the cams 27 is fairly movable relative to the other strip member 61, which is connected to the tool holder 1 in a slot-narrowing manner, so that the gap 57, at its free upper end, narrows from the free gap cross-section or clearance.

The fixing body 19 is thus designed similar to a cuboid-shaped structural member penetrated by a groove from the upper side, forming an engagement slot 57, with the slot opening downward into a type of bridge as a connecting link between the two strip members 59 and 61. In this way, a kind of bending joint is implemented on said bridge, whereby the strip member 59 can be supplied to the strip member 61 during elastic deflection around this bending point. This swiveling movement of the strip member 59 occurs only if the tool holder 1 in its corresponding installed state is located on the disk 3. In this way, the respective fixing surface 25 comes into contact with the associated positioning surface 17, possibly only partially, on the tool disk 3. 

1. A fixing apparatus for releasably fixing at least one functional component, in particular in the form of a tool holder (1), on a further functional component, in particular in the form of a tool disk (3), about at least one fixing axis (5), wherein the two functional components each have a bearing surface (7, 9) for mutual contact with one another, and both one functional component and the further functional component have at least one fixing element (11,13), characterized in that in order to form the fixing elements (13), one functional component has two spaced apart fixing bodies (19) in fixed-position connection with the associated functional component on both sides of the fixing axis (5), and that each fixing body (19) forms a fixing surface (25) which extends transversally relative to the fixing axis (5), which both from the same side may be placed against an associated positioning surface (17), which as fixing elements (11) are located spaced apart on the other functional component.
 2. The fixing apparatus according to claim 1, characterized in that the fixing bodies (19) are in fixed-position connection with the relevant functional component, preferably the tool holder (1), by means of at least one form locking element (55).
 3. The fixing apparatus according to claims 1, characterized in that the respective fixing surface (25) is formed on a fixing cam (27) integrated in the respective fixing body (19), protrudes from the bearing surface (7), and defines a fixing plane extending transversely to fixing axis (5).
 4. The fixing apparatus according to claim 1, characterized in that the fixing elements (11) of the other functional component, preferably the tool disk (3), each have a recess (15) in their bearing surface (9) for forming the respective positioning surface (17) for each fixing surface (25), which is bounded on one side by a wall portion forming the positioning surface (17).
 5. The fixing apparatus according to claim 1, characterized in that the fixing bodies (19) each are formed by a respective strip member mounted on opposite side faces (21) of a rectangular base plate (23) of the tool holder (1).
 6. The fixing apparatus according to claim 1, characterized in that the strip members (19) on the base plate (23) are fixed by a threaded connection (29) comprising form locking elements (55) for forming a precision-fit connection without the use of an adjusting device.
 7. The fixing apparatus according to claim 1, characterized in that each threaded connection (29) for forming the precision-fit form locking between screw (53) and the associated holes (45, 47) in strip member (19) and base plate (23) has a bushing (55) snugly seated on the screw (53), and whose outer circumference matches the holes (45, 47) of the strip member (19) and the base plate (23).
 8. The fixing apparatus according to claim 1, characterized in that the strip members (19) extend over the majority of the length of the respective side face (21) of the base plate (23) and that at each end portion of the strip members (19), a threaded connection (29) is provided.
 9. The fixing apparatus according to claim 1, characterized in that the fixing cams (27) are located in the proximity of either end portion of the strip members (19). 